Papers by Keyword: Tie

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Authors: Jun Qing Guo, Zhou Can Fu
Abstract: This paper expatiates the prominent effect of axial compression ratios on the ductility of reinforced concrete frame columns and the limits of the ratios in Code for Seismic Design of Buildings and summarizes the ductility design methods of frame columns with high compression ratios. The principles of value engineering were adopted to analyze the major factors affecting the ductility of reinforced concrete frame columns. The cost of columns with high compression ratios and different types of ties in a real project was calculated and relevant analysis and evaluations were conducted according to Value Coefficient Discriminance. At last the optimum ductility design method for frame columns with high compression ratios was put forth, with which reference can be made in design.
Authors: Giuseppe La Manna Ambrosino, Domenico Brigante, Alessandro Mauro, Antonio Formisano
Abstract: The present paper deals with concept, prototyping and application of a tensioning system for FRP ties into masonry structures. The proposed system, based on the use of FRP strands instead of traditional steel ties, has the aim to produce a compression stress state on masonry walls where it is applied. Given the objective difficulty in tensioning a FRP strand, it was necessary to both characterize and prototype a suitable connection system between the strand and the pulling system. The experimental phase concerned both the manufacturing of the pulling system and the study of used materials, as well as the characterization of the impregnation technology of FRP ties. The above described system has been produced and used in the framework of the structural retrofitting of the “Real Albergo dei Poveri” building in Naples.
Authors: Saeid Alizadeh, Gregory A. MacRae, Des Bull, George Charles Clifton
Abstract: Different methods to model building floor diaphragm in-plane stiffness with truss elements are compared to identify the method most suitable for analysis in design. The methods considered include (i) an elastic diagonal truss element model, and (ii) an elastic diamond truss element model. The truss elements were placed in square blocks and are compared with FEM in terms of stiffness and capturing beam axial forces. It was found that diagonal model transferred some part of diaphragm force directly to the column. The diamond framework superior because it was less sensitive to mesh size, gives a more accurate stiffness with a lower number of elements and a more accurate beam axial force. Furthermore, it better provides information in a better format for design.
Authors: Olga Markogiannaki, Ioannis Tegos
Abstract: The scope of the study is to examine of the possibility of applying steel ties, which can consist of common steel wires, as means to restrain the seismic displacements of buildings structural systems. The method seems to be competitive to the conventional ones, since fewer disturbances are created during the retrofitting works, i.e. the installation of ties as compared to the conventional strengthening methods. The method also proved to be more economic than the conventional method of constructing and infilling concrete walls in the vulnerable structural system. Initially, the efficiency of the ties was studied in multistory building models, such as frame, combined frame-wall and combined frame-wall without beams. Based on the results of the analytical study, the method was applied on a 5 storey existing and seismically deficient building. More specifically, the long side of the building was chosen for the method’s application. The last choice was deemed more preferable due to the fact that it has no openings which allowed the easy application of straight ties. The one end of the ties is anchored in the concrete slab of the upper stories, while the other end on the basement’s upper concrete slab. Although the seismic demand was higher for the implemented solution of the steel wires due to multiple loading, caused by the low value of the seismic performance coefficient equal to 1.5, an adequate level of earthquake resistance was achieved. The results of the case study confirmed the applicability of the proposed method. It should be underlined that the ties method looks promising in the field of structures retrofitting and could be studied analytically in campaigns, either independently or in combination with the conventional in concrete shear wall method.
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